Spline

Cubic interpolating plane curve or space curve

• Library:

• Simscape / Multibody / Curves and Surfaces

• 

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Description

This Spline block creates a continuous spline curve based on cubic interpolation between the specified points. The curve can be two dimensional, such as a planar cam profile, or three dimensional, such as a roller coaster track. The dimension of the spline depends on the dimension of the coordinate matrix. An n-by-2 matrix specifies a 2-D curve in the xy plane. An n-by-3 matrix specifies a 3-D curve. All the coordinates are resolved in the local reference frame of the block. Moreover, according to the specified end conditions, the curve can be either open or closed.

Cam profile — An Example of a 2-D Spline Curve

Ports

Frame

R — Reference frame

frame

Spline curve reference frame. Connect this frame port to another block to specify the location of the spline curve in a model.

Geometry

G — Spline curve representation

geometry

Geometry data associated with the representation of a 2-D or 3-D continuous spline curve. It provides the spline curve specification to other blocks to which it connects, such as the Point On Curve Constraint block.

Parameters

Interpolation Points — Spline curve interpolation points

[6 -2 9; -6 5 -4; -6 -7 9; 6 0 -4; -3 6 9; -3 -8 -4] m (default) | n-by-2 matrix | n-by-3 matrix

Matrix that includes the coordinates of the interpolation points for defining the spline curve. Use an n-by-2 matrix to specify a 2-D spline and an n-by-3 matrix to specify a 3-D spline. Each interpolation point of the coordinate matrix must be unique.

End Conditions — Treatment of the curve endpoints

Periodic (Closed) (default) | Natural (Open)

End conditions of the spline curve. The Periodic (Closed) end conditions correspond to a closed curve. For this condition, the block joins the first and last data points with a continuous curve. The Natural (Open) end condition corresponds to an open curve.

The spline curve is a piecewise function of third-order polynomial segments connected end-to-end. The curve is built such that adjacent polynomial segments have the same first and second derivatives at the shared endpoints.

Graphic

Type — Spline visualization setting

From Geometry (default) | Marker | None

Visualization setting for this spline. Use the default setting, From Geometry, to show the spline. Select Marker to show a graphic marker such as a sphere or frame. Select None to disable visualization for this spline.

Shape — Shape of graphic marker

Sphere (default) | Cube | Frame

Geometrical shape of the graphic marker. The Mechanics Explorer shows the marker using the selected shape.

Dependencies

To enable this parameter, set Type to Marker.

Size — Size of graphic marker

10 (default) | positive integer

Size of the graphic marker in screen pixels. The size value should be a positive integer.

Dependencies

To enable this parameter, set Type to Marker.

Visual Properties — Parameterizations for color and opacity

Simple (default) | Advanced

Parameterization for specifying visual properties. Select Simple to specify color and opacity. Select Advanced to add specular highlights, ambient shadows, and self-illumination effects.

Dependencies

To enable this parameter, set Type to From Geometry or Marker.

Color — True color as [R,G,B] vector on 0–1 scale

[0.0 0.0 0.0] (default) | three-element vector with values in the range of (0,1)

RGB color vector with red (R), green (G), and blue (B) color amounts specified on a 0–1 scale. A color picker provides an alternative interactive means of specifying a color.

Dependencies

To enable this parameter, set :

1. Type to Marker.

2. Visual Properties to Simple.

Opacity — Surface opacity as scalar number on 0–1 scale

1.0 (default) | scalar with value constrained to 0–1

Graphic opacity specified on a scale of 0–1. An opacity of 0 corresponds to a completely transparent graphic and an opacity of 1 to a completely opaque graphic.

Dependencies

To enable this parameter, set :

1. Type to Marker.

2. Visual Properties to Simple.

Diffuse Color — True color as [R,G,B,A] vector on 0–1 scale

[0.0 0.0 0.0] (default) | three- or four-element vector with values constrained to 0–1

True color under direct white light specified as an [R,G,B] or [R,G,B,A] vector on a 0–1 scale. An optional fourth element specifies the color opacity on a scale of 0–1. Omitting the opacity element is equivalent to specifying a value of 1.

Dependencies

To enable this parameter, set :

1. Type to Marker.

2. Visual Properties to Advanced.

Specular Color — Highlight color as [R,G,B,A] vector on 0–1 scale

[0.5 0.5 0.5 1.0] (default) | three- or four-element vector with values constrained to 0–1

Color of specular highlights specified as an [R,G,B] or [R,G,B,A] vector on a 0–1 scale. The optional fourth element specifies the color opacity. Omitting the opacity element is equivalent to specifying a value of 1.

Dependencies

To enable this parameter, set :

1. Type to Marker.

2. Visual Properties to Advanced.

Ambient Color — Shadow color as [R,G,B,A] vector on 0–1 scale

[0.15 0.15 0.15 1.0] (default) | three- or four-element vector with values constrained to 0–1

Color of shadow areas in diffuse ambient light, specified as an [R,G,B] or [R,G,B,A] vector on a 0–1 scale. The optional fourth element specifies the color opacity. Omitting the opacity element is equivalent to specifying a value of 1.

Dependencies

To enable this parameter, set :

1. Type to Marker.

2. Visual Properties to Advanced.

Emissive Color — Self-illumination color as [R,G,B,A] vector on 0–1 scale

[0.0 0.0 0.0 1.0] (default) | three- or four-element vector with values constrained to 0–1

Surface color due to self illumination, specified as an [R,G,B] or [R,G,B,A] vector on a 0–1 scale. The optional fourth element specifies the color opacity. Omitting the opacity element is equivalent to specifying a value of 1.

Dependencies

To enable this parameter, set :

1. Type to Marker.

2. Visual Properties to Advanced.

Shininess — Highlight sharpness as scalar number on 0–128 scale

75 (default) | scalar with value constrained to 0–128

Sharpness of specular light reflections, specified as a scalar number on a 0–128 scale. Increase the shininess value for smaller but sharper highlights. Decrease the value for larger but smoother highlights.

Dependencies

To enable this parameter, set :

1. Type to Marker.

2. Visual Properties to Advanced.

Extended Capabilities

C/C++ Code Generation
Generate C and C++ code using Simulink® Coder™.